The following light emitting array has been described in Patent Document 1. That is, in the light emitting array, a large number of light emitting elements in each of which a threshold voltage or a threshold current can be controlled from the outside are arranged one-dimensionally, two-dimensionally or three-dimensionally, adjacent ones of electrodes controlling the threshold voltages or the threshold currents of the light emitting elements respectively are connected to each other by an electric unit, and a clock line through which a voltage or a current is applied from the outside is connected to each of the light emitting elements.
The following self-scanning light source head has been described in Patent Document 2. That is, the self-scanning light source head is provided with a substrate, surface emitting type semiconductor lasers and thyristors. The surface emitting type semiconductor lasers are arranged in an array on the substrate. The thyristors serve as switching elements that are arranged on the substrate to selectively turn ON/OFF light emission of the surface emitting type semiconductor lasers.
The following self-scanning light emitting device has been described in Patent Document 3. That is, in the self-scanning light emitting device, light emitting elements each having a pnpnpn six-layer semiconductor structure are configured. Electrodes are provided on a p-type first layer and an n-type sixth layer on opposite sides of each of the light emitting elements, and on a p-type third layer and an n-type fourth layer in the center of the light emitting element. The pn layers are made to carry out a light emitting diode function, and the pnpn four layers are made to carry out a thyristor function.